scholarly journals CARBON NANOPARTICLES BASED ON THERMALLY EXPANDED GRAPHITE: EFFECT OF THE TEG OBTAINING ROUTE ON THE PARTICLES MORPHOLOGY

2021 ◽  
pp. 777-787
Author(s):  
Елена Владимировна Ракша ◽  
Валентина Александровна Глазунова ◽  
Оксана Николаевна Осколкова ◽  
Петр Владимирович Сухов ◽  
Галина Кузьминична Волкова ◽  
...  
Keyword(s):  
Carbon Nanoparticles ◽  
Expanded Graphite ◽  
Thermally Expanded Graphite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbon Particles ◽  
Tert Butanol ◽  
Transmission Electron ◽  
Graphite Nitrate ◽  
Lower Temperature

В работе представлены результаты исследования морфологии углеродных наночастиц, образующихся при жидкофазном расслоении терморасширенного графита в трет-бутаноле. Используемый в работе терморасширенный графит получен путем термического расширения соинтеркалата нитрата графита с уксусной и муравьиной кислотами в режиме термоудара при 500°С и 900 °С. Исходный соинтеркалант по данным рентгенофазового анализа представляет собой смесь соединений II-й и IV-й стадий интеркалирования. Методом просвечивающей электронной микроскопии установлено, что дисперсии углеродных наночастиц, образующиеся при расслоении терморасширенного графита в трет-бутаноле под действием ультразвука, содержат в основном малослойные графены, планарные размеры которых достигают 8 мкм. Обсуждается влияние условий получения терморасширенного графита на морфологию образующихся углеродных наночастиц. Дисперсии на основе терморасширенного графита, полученного при более низкой температуре, помимо малослойных графенов содержат также значительное количество аморфных углеродных частиц с планарными размерами до 100 нм. The paper presents the investigation results of the morphology of carbon nanoparticles formed during liquid-phase exfoliation of thermally expanded graphite in tert-butanol. The thermally expanded graphite used in this work was obtained by thermal expansion of graphite nitrate with acetic and formic acids in the thermal shock mode at 500 °C and 900 °C. Initial cointercalate was shown by powder X-ray diffraction analysis to be the mixture of the II and the IV stage intercalation compounds. It has been established by transmission electron microscopy that dispersions of carbon nanoparticles formed during the exfoliation of thermally expanded graphite in tert-butanol via sonication contain mainly few-layer graphenes, the planar dimensions of which reach 8 pm. The influence of the conditions for thermally expanded graphite obtaining on the morphology of resulting carbon nanoparticles is discussed. Dispersions based on thermally expanded graphite obtained at a lower temperature, in addition to few-layer graphenes, also contain a significant amount of amorphous carbon particles with planar sizes up to 100 nm.

scholarly journals FEW-LAYER GRAPHENE PARTICLES BASED ON THERMALLY EXPANDED COINTERCALATE OF GRAPHITE NITRATE WITH ACETIC AND FORMIC ACIDS

2020 ◽  
pp. 580-590
Author(s):  
Алина Александровна Давыдова ◽  
Елена Владимировна Ракша ◽  
Оксана Николаевна Осколкова ◽  
Виктория Валерьевна Гнатовская ◽  
Петр Владимирович Сухов ◽  
...  
Keyword(s):  
Structural Characteristics ◽  
Intercalation Compound ◽  
Expanded Graphite ◽  
Thermally Expanded Graphite ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Graphite Nitrate ◽  
Graphene Nanoparticles ◽  
Few Layer Graphene ◽  
Acetic Acids

Путем расслоения терморасширенного графита в этиловом и трет-бутиловом спиртах под действием ультразвука получены дисперсии малослойных графеновых наночастиц. Исходный терморасширенный графит получен термической обработкой в ударном режиме нагрева тройного соединения соинтеркалирования нитрата графита с уксусной и муравьиной кислотами. Проведено исследование структурных характеристик соинтеркалата нитрата графита и терморасширенного графита методом рентгенофазового анализа. Микроструктура и морфология полученных графеновых частиц исследованы методом просвечивающей электронной микроскопии. Dispersions of graphene nanoparticles were obtained by liquid phase exfoliation of thermally expanded graphite in ethanol as well as tert-butanol via sonication. Initial thermally expanded graphite was obtained by heat treatment in the shock mode of ternary graphite nitrate intercalation compound with formic and acetic acids. Investigation of the graphite nitrate intercalation compound and thermally expanded graphite structural characteristics by X-ray diffraction analysis has been carried out. The microstructure and morphology of the obtained graphene particles were studied by transmission electron microscopy.

Formation of Graphite Encapsulated Nickel Nanoparticles by Ball Milling and Annealing of Expanded Graphite with Nickel

2011 ◽  
Vol 80-81 ◽  
pp. 217-220 ◽  
Author(s):  
Xue Qing Yue ◽  
Hai Jun Fu ◽  
Da Jun Li
Keyword(s):  
Electron Microscope ◽  
Ball Milling ◽  
Transmission Electron Microscope ◽  
Nickel Nanoparticles ◽  
Size Range ◽  
Expanded Graphite ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nickel Powders ◽  
Transmission Electron

Graphite encapsulated nickel nanoparticles were prepared by ball milling andsubsequently annealing a mixture of expanded graphite with nickel powders. The products were characterized by transmission electron microscope and X-ray diffraction. The formation mechanism of the products was discussed. Results show that the products have a size range of 20-150 nm. The graphite and nickel in the products all exhibit a high crystallinity.

Effect of Aging Treatment on Damping Capacity in Mncunife Alloy

2012 ◽  
Vol 246-247 ◽  
pp. 1158-1162
Author(s):  
Xu Fu ◽  
Ning Li ◽  
Yu Hua Wen ◽  
Jing Teng ◽  
Ying Zhang
Keyword(s):  
Electron Microscope ◽  
Aging Treatment ◽  
Damping Capacity ◽  
Torsion Pendulum ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Higher Temperature ◽  
Lower Temperature ◽  
The Relationship

M2052 alloys with various aging treatments are obtained in order to investigate the relationship between aging treatment and damping capacity by the torsion pendulum, X-Ray Diffraction (XRD) and Transmission Electron Microscope (TEM) methods. The results show that M2052 can obtain high damping capacity (δ>0.2) when aged at a range from 400°C to 450°C, and the damping capacity after aged at a lower temperature is higher than that aged at a higher temperature for the maximum values. TEM and XRD results show that fcc-fct transformation occurs after aging treatment. The volumes of fct structures are one of reason to affect the damping capacity in M2052 alloy. The better understanding aging treatment could promote the applications of M2052 alloy.

scholarly journals Influence of Intercalation-Exfoliation-Reduction Technique towards the Physico-Chemical of VPO Catalysts

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Y. C. Wong ◽  
Y. H. Taufiq-Yap
Keyword(s):  
Electron Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Vpo Catalysts ◽  
Transmission Electron ◽  
Physico Chemical ◽  
Vpo Catalyst ◽  
Temperature Programmed ◽  
Lower Temperature ◽  
Synthesized Materials

Four VPO catalysts were synthesized through intercalation and exfoliation in various alcohols and subsequent reduction of the exfoliated VOPO4sheets with various alcohols to produce VOHPO4⋅0.5H2O. The resulting VOHPO4⋅0.5H2O that undergoes the intercalation-exfoliation-reduction (IER) process will be further activated into VPO catalysts, and addition of 1 mole % Bi(NO3)3⋅5H2O in the first stage of this experiment has also being investigated. The synthesized materials were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and temperature-programmed reduction (TPR) in H2. Catalytic evaluation of the IER-treated and Bi-doped VPO catalysts was also studied on microreactor. The VPO catalyst produced through IER using 2-butanol and ethanol with addition of Bi, IERC(2Bu-Et)RBi1, gave the highest MA selectivity due to reactive O2−species released from the additional crystalline V5+phase formed by doping 1% bismuth as promoter (O2−-V5+pair) at relative lower temperature. Nevertheless, the VPO catalyst produced through IER using isobutanol, IERC(isoBu), gave the highest activity due to high amount of reactive O−species released from V4+phase (O−-V4+pair) whereby the IERC(isoBu) catalyst synthesized consists of high percentage of V4+(93 %).

scholarly journals Transformation mechanism of magnetite nanoparticles

2015 ◽  
Vol 33 (2) ◽  
pp. 278-285 ◽  
Author(s):  
Umar Saeed Khan ◽  
Abdul Manan ◽  
Nasrullah Khan ◽  
Amir Mahmood ◽  
Abdur Rahim ◽  
...  
Keyword(s):  
Magnetite Nanoparticles ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Transformation Mechanism ◽  
X Ray ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Magnetite Particles ◽  
Size And Morphology ◽  
Lower Temperature

AbstractA simple oxidation synthesis route was developed for producing magnetite nanoparticles with controlled size and morphology. Investigation of oxidation process of the produced magnetite nanoparticles (NP) was performed after synthesis under different temperatures. The phase transformation of synthetic magnetite nanoparticles into maghemite and, henceforth, to hematite nanoparticles at different temperatures under dry oxidation has been studied. The natural magnetite particles were directly transformed to hematite particles at comparatively lower temperature, thus, maghemite phase was bypassed. The phase structures, morphologies and particle sizes of the produced magnetic nanoparticles have been investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDX) and BET surface area analysis.

Microstructure and Anti-Friction Effect of Ball-Milled Expanded Graphite

2013 ◽  
Vol 704 ◽  
pp. 110-113
Author(s):  
Hong Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ball Milling ◽  
Expanded Graphite ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Friction Effect ◽  
Air Atmosphere ◽  
Transmission Electron

Expanded graphite (EG) was ball-milled in a high-energy mill (planetary-type) under an air atmosphere. The products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The anti-friction effect of milled EG used as lubricating additive was investigated. After ball-milling, the relatively ordered graphene planes of original EG become deformed, and the d002 spacing becomes broadened. The milled EG used as lubricating additive have an anti-friction effect, and the effect is more marked than that of original EG.

Synthesis Of Highly Ordered Macroporous Minerals: Extension of the Synthetic Method to Other Metal Oxides and Organic-Inorganic Composites

1998 ◽  
Vol 549 ◽  
Author(s):  
C.F. Blanford ◽  
T.N. Do ◽  
B.T. Holland ◽  
A. Stein
Keyword(s):  
Electron Microscopy ◽  
Metal Oxides ◽  
Three Dimensional ◽  
X Ray Diffraction ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Wide Range ◽  
Ordered Macroporous ◽  
Lower Temperature

AbstractThe facile synthesis of three-dimensional macroporous arrays of titania, zirconia and alumina was recently reported [1]. The synthesis of these materials has now been extended to the oxides of iron, tungsten, and antimony, as well as a mixed yttrium-zirconium system and organically modi- fied silicates. These materials were characterized by Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), X-ray energy dispersive spectrometry (EDS), and powder X-ray diffraction (XRD). Ordered structures of iron, tungsten, and antimony were formed from alkoxide precursors as in the originally reported synthesis, but the template was removed at a lower temperature. Samples of vinyl- and 2-cyanoethyl-modified silicates were formed from a mixture of organotrialkoxysilane and tetraalkoxysilane precursors; the polystyrene template was removed by extraction with a THF/acetone mixture. These results show the ease of extending the original syn- thesis to a wide range of systems. Also, the ability to form homogenous mixed-metal oxides will be important for tailoring the dielectric and photonic properties of these materials.

Study on the Morphology and Phases of Cu-Se Powders Synthesized by Hydrothermal Co-Reduction

2010 ◽  
Vol 29-32 ◽  
pp. 1824-1827
Author(s):  
Ke Gao Liu ◽  
Bo Pang ◽  
Zhi Gang Wang ◽  
Bin Xu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Deionized Water ◽  
Experimental Results ◽  
Side Length ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Lower Temperature ◽  
Co Reduction

Cu-Se compound powders are synthesized by hydrothermal co-reduction from CuSO4•5H2O and SeO2 in deionized water at 120～200 °C. The phases and morphology of the products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) respectively. Experimental results show that, the CuSe phase can be synthesized at 120,150,180 and 200 °C, however, the purity phases become more with the temperature decreasing. It indicates that the reaction is more incomplete at lower temperature. Hexagonal flakes with side length 100～400 nm can be observed in the products at 150,180 and 200 °C, among which only the product prepared at 180 °C has the hexagonal flakes with good dispersity and homogeneous size with 200 nm length.

High Temperature Tribological Behavior of Ball Milled Expanded Graphite/Iron Powders

2012 ◽  
Vol 499 ◽  
pp. 278-281 ◽  
Author(s):  
Hua Wang ◽  
Yong Guo ◽  
Shu Ying Wang
Keyword(s):  
Electron Microscopy ◽  
Tribological Behavior ◽  
Expanded Graphite ◽  
High Energy ◽  
X Ray Diffraction ◽  
Iron Powders ◽  
X Ray ◽  
Friction Effect ◽  
Transmission Electron ◽  
Milled Powders

A mixture of expanded graphite (EG) and iron powders was ball-milled in a high-energy mill. The milled EG/Fe powders were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The tribological behavior of the milled powders used as lubricating additive was investigated by using a tribo-tester. The results show that the milled powders used as lubricating additive have an obvious anti-friction effect, and the more large the applied temperature, the more marked the anti-friction effect.

Study on Synthesis of Ni-S Powders Synthesized by Hydrothermal Co-Reduction

2012 ◽  
Vol 503-504 ◽  
pp. 637-640
Author(s):  
Yuan Xing Cai ◽  
Ke Gao Liu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Major Phase ◽  
X Ray ◽  
Transmission Electron ◽  
Lower Temperature ◽  
Co Reduction ◽  
Product Powder

The technologies of synthesizing Ni-S powders from 0.001 mol NiCl2•6H2O and 0.001 mol sulfur (S) powder were investigated at 95,105,120,140 and 160 °C. The phases and morphology of the products were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) respectively. Experimental results show that, the Ni-S powders prepared at 120~160 °C from NiCl2•6H2O and S powder have the same major phase NiS. These products have flakes or unregular shape grains with sizes of 100~200nm. However, the product powder prepared at 105 °C has the major phase Ni3S2 without obvious impurity phases and only grains with size less than 200nm. No Nickel sulfides can be synthesized at 95 °C under the experimental conditions. It can be found that the NiS phase appears in the products powders obtained at higher temperatures while Ni3S2 obtained at lower temperature.

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